Article 5 of Kuwait Income Tax Decree No. 3 of 1955 defines the Taxable Period as the accounting period used by the taxpayer for their records. The default basis is the Calendar Year, a term updated from 'Christian Calendar Year' by Law No. 2 of 2008. Upon a taxpayer's request, the Director may authorise in writing an alternative basis, which cannot exceed one calendar year plus half of the subsequent year. Once granted, this authorisation cannot be unilaterally revoked or varied by the Director. The Director retains the right to impose appropriate conditions on any such authorisation.